21189355 has 8 divisors (see below), whose sum is σ = 27738864. Its totient is φ = 15410400.

The previous prime is 21189341. The next prime is 21189397. The reversal of 21189355 is 55398112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21189355 - 2⁵ = 21189323 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21189355.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 192576 + ... + 192685.

It is an arithmetic number, because the mean of its divisors is an integer number (3467358).

Almost surely, 2^21189355 is an apocalyptic number.

21189355 is a deficient number, since it is larger than the sum of its proper divisors (6549509).

21189355 is a wasteful number, since it uses less digits than its factorization.

21189355 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 385277.

The product of its digits is 10800, while the sum is 34.

The square root of 21189355 is about 4603.1896550110. The cubic root of 21189355 is about 276.7191695653.

The spelling of 21189355 in words is "twenty-one million, one hundred eighty-nine thousand, three hundred fifty-five".